Vernon Hugh Bowman, a 75-year-old farmer from rural Indiana, did something that got him sued. He planted soybean seeds. But Monsanto, the ag giant, insists it has a patent on the kind of genetically modified seeds Bowman used — and that the patent continues to all of the progeny of those seeds.

Have we really gotten to the point that planting a seed can lead to a high-stakes Supreme Court patent lawsuit? We have, and that case is Bowman v. Monsanto, which is being argued on Tuesday. Monsanto’s critics have assailed the company for its “ruthless legal battles against small farmers,” and they are hoping this will be the case that puts it in its place. They are also hoping the court’s ruling will rein in patent law, which is increasingly being used to claim new life forms as private property.

Monsanto and its supporters, not surprisingly, see the case very differently. They argue that when a company like Monsanto goes to great expense to create a valuable new genetically modified seed, it must be able to protect its property interests. If farmers like Bowman are able to use these seeds without paying the designated fee, they argue, it will remove the incentives for companies like Monsanto to innovate.

Bowman is a character out of a populist movie — a modern-day Mr. Smith Goes to the Supreme Court. If he had bought the genetically modified Roundup Ready seeds directly from Monsanto, he would have been required to pay the company’s technology fee. But Bowman bought his seeds from a grain elevator, which sold him a mix usually used for livestock feed — a mix that happened to include seeds that were progeny of Monsanto’s patented Roundup Ready. Bowman argued that these progeny seeds were not covered by Monsanto’s patent, so he had no duty to pay the company a fee.

Monsanto accused Bowman of patent infringement and won a $84,456 damage award. Rather than pay up or work out a settlement, Bowman decided to appeal — all the way to the Supreme Court. He told the Washington Post that “Monsanto should not be able, just because they’ve got millions and millions of dollars to spend on legal fees, to try to terrify farmers into making them obey their agreements by massive force and threats.”

The central issue in the case is whether patent rights to living things extend to the progeny of those things. Monsanto argues that its patents extend to later generations. But Bowman’s supporters — who include the National Farmers Union, the National Family Farm Coalition and the American Antitrust Institute — argue that Monsanto is trying to expand the scope of patents in ways that would enrich big corporations and hurt small farmers. They say that if Monsanto wins, the impact will extend far beyond agriculture — locking up property rights in an array of important areas. Knowledge Ecology International — a nonprofit intellectual-property group that backs Bowman — contends that the Supreme Court’s ruling could have “profound effects” on other biotech industries, “including those involving cell lines, DNA or RNA sequences, virus strains and microorganisms.”

Many people are troubled by how Monsanto does business — its market dominance, its hardball fee tactics. But as reasonable as these anti-Monsanto views may be, the company has a good record of winning cases like this. The federal appeals court that has already ruled in Bowman v. Monsanto sided with Monsanto. And the Obama Administration is arguing in the Supreme Court on Monsanto’s side.

If this were a Hollywood movie, the plucky old Indiana farmer would beat the profit-minded corporation before the credits rolled. But this is a real-life argument before a Supreme Court that has a well-earned reputation for looking out for the interests of large corporations. This case gives the court an opportunity to rein in the growing use of patents to protect genetically engineered crops and other life forms — but the court may well use it to give this trend a powerful new endorsement.